Taking advantage of the Historical Society's myriad exhibitions, lectures, and walking tours is like stepping into your own well-ordered time machine. Its tidy home base near Yerba Buena Gardens exhibits treasures from an extensive collection of newspapers, broadsides, maps, Native American artifacts, 35,000 books, half a million photographs, the letters and diaries of pioneers and gold-seekers, and artworks from the pre-Gold Rush days to Prohibition. Every first Tuesday of the month there are free lectures on such topics as Victorian architecture and the history of Noe Valley. Regularly scheduled walkabouts might explore Laurel Heights, the Russian-era North Bay, or Sydneytown, the raucous old Aussie settlement east of Telegraph Hill. Founded in 1871, the Society also hosts family events and school programs and publishes California History magazine and California Chronicle, a quarterly newsletter. Gallery hours are Tuesday through Saturday, 11 a.m. to 5 p.m.